Step 1: To make the brine, bring water, pickling spice, sugar and salt to a boil. Reduce heat and simmer uncovered for 3 minutes. Allow to cool completely.

Step 2: Place uncooked roast in heavy plastic bag. Add cooled brine, thyme, garlic and shallots. Fold down excess plastic of bag, if necessary, and clip in place to allow roast to fully immerse in brine. Set in a bowl and chill in refrigerator overnight.

Step 3: To cook, preheat oven to 500°F.

Step 4: Heat oil and butter in large frying pan. Remove roast from brine, keeping any clinging spices and herbs on roast. Brown on all sides.

Step 5: Place rounds of onion in a single layer in ceramic or glass baking dish just large enough to hold roast. Add water.

Step 6: Set browned roast on onions.

Step 7: Cook roast at 500°F for 15 minutes, then reduce heat to 375°F and roast for about another hour, or until internal temperature reads 150°F on a meat thermometer (roast about 20 minutes per pound for boneless roasts.) (Note: bone-in roasts require a longer cooking time, about 25 minutes per pound).

Step 8: Remove roast from oven and allow it to rest a few minutes under a loose covering of foil before thinly slicing.